The primary purpose of the JUNOS RSVP software is to support dynamic signaling within LSPs. When you enable both MPLS and RSVP on a router, MPLS becomes a client of RSVP. No additional configuration is required to bind MPLS and RSVP. You can configure MPLS to set up signaled paths using the label-switched - path statement. Each LSP translates into a request for RSVP to initiate an RSVP session. This request is passed through the internal interface between label switching and RSVP. After examining the request information, checking RSVP states, and checking the local routing tables, RSVP initiates one session for each LSP. The session is sourced from the local router and is destined to the target of the LSP. When an RSVP session is successfully created, the LSP is set up along the paths created by the RSVP session. If the RSVP session is unsuccessful , RSVP notifies MPLS of its status. It is up to MPLS to try to initiate backup paths or to continue retrying the initial path. To pass label-switching signaling information, RSVP supports four additional objects: label request object, label object, explicit route object, and record route object. For an LSP to be set up successfully, all routers along the path must support MPLS, RSVP, and these four objects. Of the four objects, record route object is not mandatory. To configure MPLS and make it a client of RSVP, do the following:
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